A conventional medical image diagnosis device (an angiography device, for example) includes an X-ray generation unit, which generates X-rays for a subject P, and an X-ray detection unit, which detects X-rays that have passed through the subject in a two-dimensional manner to generate X-ray projection data. The X-ray generation unit and the X-ray detection unit are supported by an arm (generally referred to as a C-arm). As the C-arm moves in the direction of a body axis of the subject on a bed or rotates around the body axis of the subject, it is possible to take images of the subject from various directions.
By the way, when images taken by the conventional medical image diagnosis device are observed, thumbnail images are arranged and displayed, for example, in the order the images are taken, and an arbitrary image is specified from among the above images to display the detailed image. However, when there are a large number of images taken from a plurality of angular directions, it takes time to determine which image has been taken at what angle if thumbnail images are simply arranged and displayed in order of imaging history. Usually, when a determination is made as to at what angle an image has been taken, the determination needs to be made by seeing the image (the shape of a blood vessel, for example), or the angle needs to be identified from supplementary information (angular information) of the image. The problem is that as the number of images collected increases, it takes time to find an image that a user wants to see.